1// Copyright (C) MongoDB, Inc. 2014-present.
2//
3// Licensed under the Apache License, Version 2.0 (the "License"); you may
4// not use this file except in compliance with the License. You may obtain
5// a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
6
7package bsonutil
8
9import (
10	"bytes"
11	"fmt"
12
13	"github.com/mongodb/mongo-tools-common/json"
14	"github.com/mongodb/mongo-tools-common/util"
15	"go.mongodb.org/mongo-driver/bson"
16)
17
18// MarshalD is a wrapper for bson.D that allows unmarshalling
19// of bson.D with preserved order. Necessary for printing
20// certain database commands.
21type MarshalD bson.D
22
23// MarshalJSON makes the MarshalD type usable by
24// the encoding/json package.
25func (md MarshalD) MarshalJSON() ([]byte, error) {
26	var buff bytes.Buffer
27	buff.WriteString("{")
28	for i, item := range md {
29		key, err := json.Marshal(item.Key)
30		if err != nil {
31			return nil, fmt.Errorf("cannot marshal key %v: %v", item.Key, err)
32		}
33		val, err := json.Marshal(item.Value)
34		if err != nil {
35			return nil, fmt.Errorf("cannot marshal value %v: %v", item.Value, err)
36		}
37		buff.Write(key)
38		buff.WriteString(":")
39		buff.Write(val)
40		if i != len(md)-1 {
41			buff.WriteString(",")
42		}
43	}
44	buff.WriteString("}")
45	return buff.Bytes(), nil
46}
47
48// MakeSortString takes a bson.D object and converts it to a slice of strings
49// that can be used as the input args to mgo's .Sort(...) function.
50// For example:
51// {a:1, b:-1} -> ["+a", "-b"]
52func MakeSortString(sortObj bson.D) ([]string, error) {
53	sortStrs := make([]string, 0, len(sortObj))
54	for _, docElem := range sortObj {
55		valueAsNumber, err := util.ToFloat64(docElem.Value)
56		if err != nil {
57			return nil, err
58		}
59		prefix := "+"
60		if valueAsNumber < 0 {
61			prefix = "-"
62		}
63		sortStrs = append(sortStrs, fmt.Sprintf("%v%v", prefix, docElem.Key))
64	}
65	return sortStrs, nil
66}
67